Conventionally, as a tapered roller bearing fabricating method, there is known a fabricating method in which as shown in FIGS. 7 and 8, by using a tapered roller supply system 110 in installing tapered rollers 1 in pocket portions 6 of a cage 2, a plurality of tapered rollers 1 are loaded in a tube 120 which extends in a vertical direction (a gravitational direction: a Z direction in FIG. 7) towards an inner circumference of the case 2 with a smaller diameter end oriented downwards, and a lowermost tapered roller 1 is separated so as to be loaded in a pocket portion 6 of the case 2.
To describe the method in greater detail, the tapered roller supply system 110 includes the tube 120 which stores in an inside hollow hole 120a the plurality of tapered rollers 1 which are loaded from above to be stacked up in the vertical direction in such a way as to be in abutment with each other, a cage resting portion 150 on which the cage 2 into which the tapered rollers 1 supplied from a lower end of the tube 120 are loaded is rested rotatably, and a top plate 158 to which the tube 120 is fixed, which has a cutout through which the tapered rollers 1 pass and which is disposed on a top portion of the cage resting portion 150. Here, the tapered rollers 1 are loaded in an inside of the hollow hole 120a in the tube 120 in such a way that the smaller diameter end is oriented downwards or constitutes a leading end.
The case resting portion 150 has a shaft 152 which extends in the Z direction, a lower table 154 which is fixed above the shaft 152, and a jig 156 that is fixed to an upper surface of the lower table 154 so as to be in abutment therewith and on a lower portion of an outer circumferential surface 156a of which the cage 2 is fixedly fitted. An upper surface of the jig 156 and a lower surface of the top plate 158 face oppositely each other with a gap defined therebetween.
Here, as shown in FIG. 8, the cage 2 has a small-diameter annular portion 3, a large-diameter annular portion 4 and a plurality of pillar portions 5 that connect the small- and large-diameter annular portions 3, 4 and which are disposed circumferentially at predetermined intervals, and the plurality of pocket portions 6 for holding the tapered rollers 1 are formed in the cage 2. Then, the cage 2 is fitted on the outer circumferential surface 156a of the jig 156 at an inner circumferential surface of the small-diameter annular portion 3 with the large-diameter annular portion 4 oriented upwards.
Portions of the outer circumferential surface 156a of the jig 156 are set back from the rest for roller accommodating portions 156b, so that the tapered rollers 1 carried from the lower end of the tube 120 are positioned for accommodation.
The shaft 152 can be rotated by a motor (not shown) connected to a lower end thereof or manually, whereby the lower table 154, the jig 156 and the cage 2 are allowed to rotate altogether in association with the rotation of the shaft 152.
In the tapered roller supply system 110 configured in this way, first of all, the tapered rollers 1 are stacked up in the vertical direction in the hollow hole 120a in the tube 120 so as to be in abutment with each other. Then, the lowermost tapered roller 1 which passes through the tube 120 comes into contact with a lower portion of the jig 156 to stop. Thereafter, the jig 156 and the cage 2 are rotated for assemblage. Additionally, the tube 120 and the top plate 158 are allowed to move in a vertical direction by a driving mechanism, not shown, so that they are withdrawn upwards when a cage 2 or an inner ring (not shown) is carried in.
In addition, as another tapered roller bearing fabricating method, there is known a fabricating method in which a large-diameter annular portion of a cage is oriented upwards, and tapered rollers are inserted into pockets of the cage with large diameter ends thereof acting as leading ends from an inner circumferential side of the cage and a small-diameter annular portion side (a lower side) of the cage (refer to Patent Document 1).